Hypodermic syringes are commonly used by medical personnel to administer injections of medicinal fluids and to take blood samples or other fluid samples from the human body. The procedure generally involves penetration of the skin by a needle or similar device. In the typical situation, treatment of the injection area is necessary both before and after the hypodermic syringe is used. For example, a cotton swab dipped with a disinfectant, such as alcohol, is usually applied to the area where the injection is to occur. After the needle has been inserted beneath the skin and removed, it is usually necessary to cover the perforation with a gauze covering.
It is primarily before and after the injection that the needle is either held or set aside. If the needle is left exposed, a significant risk of accidental contact with the needle point by the medical practitioner exists.
In an effort to reduce the likelihood of accidental contact with the needle point, a variety of needle guards or shields have been developed to cover the needle after the injection and thereby protect the practitioner from accidental puncture by the needle. Generally the shield devices of the prior art require two hands in order to achieve operation of the sliding shield and do not have the ability of selectively locking the shield in the retracted position with the needle exposed.